The easiest and most informative method to test the continuity of an Ethernet cable involves purchasing an affordable device called a continuity tester. A basic model will test the continuity of Ethernet and coaxial cable. A continuity tester is not absolutely necessary, but highly useful if you need to test Ethernet cables frequently. There is some important terminology you should understand before proceeding. Jacks are where the ends of the cable plug into a computer or other networking device. Plugs are the small plastic connectors on the end of the cable. Pairs refers to colour-coded strands of wires that are matched together, and cable housing is the plastic insulation that covers and protects these wires.
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Power on the continuity tester.
Insert one of the cable plugs into the tester and the other into the terminator.
Look at the display of the network tester. Depending on your continuity tester, at a minimum it will indicate if there is a break in the cable and, should it include this feature, which cable pairs the break affects.
Power the computer and a router or other networking device on.
Plug the cable into the network port on the computer and the other end into the networking device.
Look at the back of the computer where the cable is plugged into the Ethernet jack and see if any flashing green or yellow lights come on. These lights indicate if the computer is sending or receiving any information. If the lights are lit or flashing, the cable continuity is good. If not, replace the cable.
Tips and warnings
- Inspect the cable housing and replace any damage with a patch cable.
- Should you not find any damage, try replacing the plugs on the cable as they may not be properly seated.
- If this is a short cable, it is best to replace the cable entirely.